Steam-turbine.



C. E. SEARCH 64 R. C. WRIGHT. STEAM TURBINE.

APPLICATION FILED FEB. 9. 19M.

1,187,454. Patented June 13, 1916.

I/I/I. III/A rigidity and strength, especially to with-.

1 ran s ra rns rarnnr @FMQE.

CHARLES EDWIN SEARCH AND ROBERT C. WRIGHT, OF MILWAUKEE, WISCONSIN,ASSIGNORS TO ALLIS-CHALMERS MANUFACTURING COMPANY, OF MILWAUKEE,WISCONSIN, A CORPORATIQN OF DELAWARE.

STEAM-TURBINE.

Specification of Letters Patent.

Patented June 13, 1916.

Application file (1 February 9, 1914. Serial No. 818,155.

To all whom it may concern:

Be it known that we, CHARLES EDWIN SEARCH and ROBERT C. WRIGHT, citizensof the United States, residing at Milwaukee, in the county of Milwaukeeand State of Wis cousin, have invented a certain new and usefulImprovement in Steam-Turbines, of which the following is aspecification.

This invention relates to steam turbines and more particularly to amethod of securing the shroud to the blade ends and of properlypositioning the blades at one end.

An object of the invention is to provide a blade structure for steamturbines which is simple in construction, efficient in operation,andwhich possesses the requisite amount of stand vibration.

One of the more specific objects of the invention is to provide a verylight shroud having means in the form of a recessed longitudinalcorrugation or projection for properly positioning the blade ends, theshroud being secured to the blades by fusion of metal.

The article of manufacture produced by the process herein described, isclaimed in application Serial No. 859,119, filed Aug. 26, 1914.

Heretofore it has been proposed to fasten a shroud to blade ends bymeans of tenons formed on the blade ends and passing through holes inthe shroud, the tenons being riveted over the shroud stock. It has alsobeen proposed to fasten a light uncorrugated shroud to the ends ofblades by fusion of metal, for instance by brazing, the blade endshaving been properly positioned by forming tenons on the blades andinserting the same in holes formed in the shroud. An objection to theseconstructions is that considerable blade stock is wasted in forming thetenons on the blades, this objection being eliminated in the presentinvention wherein blades having single-surfaced ends may be utilized.

The expression single-surfaced end as used herein is intended to applyto a blade end which is free of any projection or recess abruptlyinterrupting the continuity of the end surface of the blade. Theexpression therefore includes blade ends having surfaces which areeither plane or curved, these surfaces being either perpendicular orobhque relative to the edges of the blades.

A clear conception of an embodiment of I the invention may be had byreferring to the drawing accompanying and forming a part of thisspecification, in which like reference characters designate the same orsimilar parts in the various views.

Figure 1 is a plan view of a fragment of a shroud attached to aplurality of blades.

Fig. 2 is an elevation of a fragment of a shroud attached to a pluralityof blade fragments. Fig. 3 is a transverse section through a pluralityof blades having a fragment of a shroud attached thereto the sectionbeing taken along the line III-III of Fig. 2 looking inthe direction ofthe arrows. Fig.

'4 is a transverse vertical section through a the section being takenalong the line VV of Fig. 3.

While the figures of the drawing disclose rotor or movable blading of aturbine of the parallel flow type, it is to be understood that theinvention is equally applicable to stator or stationary blading, as wellas to other types of turbines. The shroud 2 is made very light and isprovided with a longitudinal continuous corrugation or projection 7having a continuous depression on the oppo-. site side thereof. Thiscorrugation or projeotion 7 forms a continuous longitudinal arc-h whichserves to strengthen or stiffen the shroud. The depression on theopposite side .1; of the projection 7 is of'such extent that the same inclose proximity to the stationary turbine casing 6.

The projection 7 1s serially notched or provided with. recesses 4, whichmay be of the recesses.

. the shroud was secured to the blade ends by' riveting tenons at theends of they blades other suitable process.

formed by sawing, broaching, milling or this recessed projection 7 iscontra-distinguished from the formation of a shroud with a series ofprojections with recesses left between them, although the originalcontinuous projection 7 is in fact altered to form divisionalprojections by the formation of the recesses 4. The recesses 4 areproperly directed so as to'permit application of the shroud 2 to thesingle-surfaced endsof the blades 1, these blade ends being properlypositioned by 'the side walls The sl1roud2 is applied to the ends of theblades 1 at the recesses, transverse derangement of a blade froihthe rowof blades being temporarily prevented by any suitable retaining means,not shown. The shroud 2 and blades 1 are then united by fusion of metalby soldering, brazing, welding or any other suitable method. In thedrawing the shroud has been united along its base with thesingle-surfaced ends 5 of the blades 1. A

Uniting the blades 1 and shroud 2 by fusion of metal produces -.a'unitary structure of great rigidity and strength espe-' cially towithstand vibration.' This construction permits the uset of a,'verylight shroud 2 instead of a comparatively heavy shroud, such as was ofnecessity used when which had previously been passed through openings inthe shroud. In this prior construction the shroud was secured to theblade only at the punched portion, thus necessitating the formation ofthe remaining portion ofthe shroud of considerable strength, that isthiclmess, in order to withstand the' strains to which the shroud; wassubjected due to-centrifugal force. In the construction of the present,invention the blade is united with the shroud along sub stantiallyitsentire end by fusion of metal, thus permitting use of a comparativelylight shroud. present invention is gcorrugated at its por- The formationof The fact that the shroud'2 of the mation of a continuous depressionopposite the projection 7 furthermore permits the production of a verylight shroud which is circumferentially free from I projections orpaddles such as are produced by the riveted-over tenon ends of theconstruction of the prior art above referred to. The for mation of theblades with single-surfaced ends furthermore eliminates the waste ofblade stock resulting in the construction of tenoned blades.

. It should be understood that it is not desired to be limited to theexact details of construction shownand described except as required bythe scope of the appended claims, for obvious modifications, will occurto a person skilled in the art.

It is claimed and'desired to secure by Letters Patent,-

"1. The process of providing blades with a shroud comprising, producinga shroud with a continuous corrugation, forming recesses in saidcorrugation, applying said shroud to ends of said blades at saidrecesses, and uniting said blades and said shroud by fusion of metal.

2. The process of providing a shroud comprising, producing a shroud witha continuous longitudinal projection and a. depression opposite saidprojection, forming recesses in} said projection, applying said shroudto ends of said blades at saidrecesses, and uniting said blades and saidshroud by fusion of metal.

o. EDWIN SEARCH. ROBERT C. WRIGHT.

Witnessesi J. M. J. KEOGH W. H. Lmnnn.

blades with gas

